Advice for use of 416-8c needed

[marmelbirne123]

Good day! I inhereted an Altec 416-8c woofer that my father in law used. There is no cabinet - i was wondering if it´s possible to put the 416 in a JBL 4507 cabinet. - I don´t need sub bass since i use a subwoofer - I am not a purist so i don´t care if it looks good or not, just care for the sound - I would use it with an Altec H-808 horn and a Jagusch x-over (800hz) - I can´t use gigantic Onken cabs or somehting similiar since my wife would kill me would this be possible? Thank you guys!

[Ian Mackenzie]

Yes it will work.

The 4507 is tuned to 40 hertz. In this enclosure the 416-8C will have at F3 of 44 hertz.

You will need to check you can front mount the driver because the cut out is specified at 356 mm or 14 inches. The driver min front mount diameter is 14 1/8 inches. The 416-8C is used in bass reflex enclosures up to 9 ft3 with an Fb of 32 hertz and an F3 of 34 hertz.

[RMC]

marmel...123,

Attached are pictures of speaker software modeling of the Altec in a 5 cu. ft. box. Personnaly i prefer to actually see the shape of the response curves as this sometimes reveals issues. Not the case here though, its pretty flat. I tuned it to 40 hz and also to 35 hz just to see the outcome, but prefer the 40 hz. In addition you already have a subwoofer so you don't need very low frequencies reproduction from the Altec speaker.

On one graph you see both curves, bottom one 35 hz and top one 40 hz. On the other graph is 40 hz alone.

I didn't model the cab dimensions here since these are already known from the 4507 tech sheet, plus these represent a net Vb as indicated (driver and bracing accounted for). Moreover i didn't have to model the ports dimensions since i already know, from JBL documents, the port data for the 4507: 2 X 3" with 6" long each.

The 98 db sensitivity at the bottom left on my graphs represents a small adjustment i made since the Altec sensitivity is 97db at 4 feet distance instead of one meter. The correction factor for one meter is +1.7db. However, Altec's sensitivity is measured in a larger 6 cu. ft. vented cab, and size influences efficiency, so i applied a 1 db adjustment, should be about correct, instead of the usual 1.7 db since the JBL box is one cu. ft. smaller (higher efficiency in larger boxes).

As usual the graphs are done with a QL 7 loss factor and 2Pi placement is assumed (box directly on the floor).

Horizontal black solid line is 98 db, corresponding to driver sensitivity at 1w/1m. 2 db between each horizontal dotted lines. In the present context shape of curve matters more than db numbers. Fb 40 hz = F3 about 45 hz.


Richard

[Ian Mackenzie]

Hi Richard,

Can you attach a clearer image?

The spl scale is not sufficient resolution once you expand the graph to actually view it. Perhaps you can screen dump directly from the software.

[marmelbirne123]

thank you guys! very good informations here.

[Mr. Widget]

A screen capture would be much better than a photo.


Widget

[grumpy]

Ctrl-Shift-S or Win-Shift-S on Windows

Cmd-Shift-3, 4 or 5 on mac (full screen, pick opposing corners, or more selection options, respectively)